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N M 0 my) T. H. MULLER.

' REAMER. No. 346,214.. Patented July 27, 1886.

ATTORNEYS UNITED STATES PATENT ()rrrcn.

TEILE H. Mt'iLLnn, on NEW YoRK, N. Y.

REAMER.

FiPECIPICATION forming part of Letters Patent No. 346,214, dated July27, 1886.

' Application filed April 22, 1886. Serial No. 199,727. (No model.)

[o can be used for a greater length of time; and

the invention consists of thecombination ofa mandrel having a conicalend, alongitudinallysplit shell'reamer that is fitted to the conical endof the mandrel, and nuts fitted on threaded cylindrical portions of themandrel and provided with tapering or cupped recesses for engaging thetapering ends of the split reamer. The split shell-reamer is providedwith radial recesses of greater depth than its teeth, by

2 which it is rendered less rigid, so as to ex- 25 proved expandingreamer.

pand on the conical end of the mandrel when reset thereon aftergrinding.

In the accompanying drawings, Figure 1 represents a sectional elevationof my im- Fig. 2 is asectional elevation of a larger size of reamer, andFig. 3 is an end View of the reaming-tool detached from the mandrel.

Similar letters of reference indicate corre- 30 sponding parts.

Referring to the drawings, A represents a mandrel, which is arrangedwith a conicallytapering portion, a, at the end, and provided at bothends of the conical portion with threaded eylipdrical portions Z) b,that have,

respectively, a right and a left screw-thread.

The shell-reamer B is made of tool-steel and split longitudinally, itsinner surface being made conical, so as to fit on the end a of 0 themandrel A. Besides the longitudinal slit of the shell-reamer B, the sameis provided at two or more points with radial recesses d d, of greaterdepth than its teeth, by which the shell-reamer is rendered less rigid,so as to 5 adjust itself by expansion to the conical end a of themandrel A when reset thereon after grindin The ends of the shell-reamerB are beveled, the beveled ends (1 d being engaged by screw-nuts O C,that are provided with 50 tapering or cupped nut-recesses (P (P, fittingover the tapering ends d d of the reamer B. The nuts 0 O are adjustedbya wrench, while in the larger sizes of reamers they are pro vided withsocket'holes at their circumference,

as shown in Fig. 2, for inserting a spannerwrench, by which they arereadily adjusted on the threaded port-ions I) b of the mandrel forengaging the beveled ends of the shellreamer B. For larger sizes ofreamers the shell -B is applied to an interposed sleeve, D, which isattached by a key, f, to the cylindrical end of the mandrel A, as shownin Fig. 2. The sleeve D is made of cast-iron, and serves to save steelinmaking the shell-reamer D, and to render the latter lighter and lessrigid. The sleeve D forms a part of the mandrel, and is provided wit-l1a conically-tapcring part, a, and cylindrical screw-threaded ends I) b,in the same manner as the mandrel A. \Vhen the reamer is worn out, it issharp encd and then adj nstcd forward on the conical portion of themandrel, and reset by tightening the nuts 0 0 onto the beveled ends ofthe split shell B. The split reamer B expands thereby and resumes itsformer diameter, it being again sharpened when worn out,and reset, andso on, it readjusting itself readily by expansion, so as to saveconsiderable in stock, time, and labor.

Having thus described my invention, I claim as new and desire to secureby Letters Patent' 1. The combination of a mandrel having aconically-tapering end portion, a longitudinally-split shell-reamerfitted to said conical portion, and screw-nuts for adjusting the reameron said mandrel, substantially as set forth.

2. The combination of a mandrel having a conically-tapering end portionand cylindrical screw-threaded parts at both ends of the conicalportion, a longitudinally-split shell-reamer fitted to the conicalportion and having beveled ends, and screw-nuts having tapering orcupped recesses for engaging the beveled ends of the reamer andadjusting the same on the conical portion of the mandrel, substantiallyas set forth.

teeth, for reducing its rigidity and permitting it to expand on themandrel, substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

\Vitnesses: TEILE H. MULLER.

PAUL GoEPEL, MARTIN PETRY.

